An aiming apparatus for making transverse bores in bones in register with bores of an osteosynthesis aid has previously been disclosed in U.S. Pat. No. 4,625,718. This apparatus includes a holder for the accommodation of an aiming member adapted to be brought into the beam path of an x-ray apparatus. The reception head of the apparatus is made of a material transparent to x-ray radiation and is rotatably supported in the holding means for the accommodation of a drill or a drill wire, and a powered driving machine is arranged at the holding means for rotatably driving the reception head. The aiming apparatus of this patent serves to detect a point where to perform the transverse bore in the bone, and at the same time serves to make a preliminary bore. As the reception head for a drill or drill wire is transparent to the x-ray radiation, the drill appears as a point on the image screen. The point is brought into register with a transverse bore of the interlocking nail in the process of aiming. This done, the drilling action is performed for the soft components and the bone with the aid of the drill or drill wire respectively. Following this, the aiming apparatus is removed and the boring action is carried out via the drill wire or drill, respectively, with the aid of a hollow drill for the suitable bore screw. Following this, the drill wire or primary drill, respectively, is removed. When using a drill wire or a suitable drill, respectively, in connection with the aiming apparatus, the diameter is relatively small so that the boring action may be performed with the aid of the hollow drill. While this device is apparently effective, it is relatively large and awkward to work with, requiring numerous x-ray exposures in order to assure accurate aligning of the drill or drill wire respectively with the bore of the osteosynthesis aid during surgery, and in addition is rather difficult to sterilize properly as is required for use in operating rooms.
An image plane indicator for visibly defining the image plane located at the movable fulcrum of a tomography x-ray machine is disclosed in U.S. Pat. No. 4,442,533. The indicator of this patent includes a laser beam light source mounted for vertical movement along a rack and pinion assembly. As the fulcrum of the x-ray machine is raised or lowered with respect to the patient to take x-ray images along different horizontal planes, a pulse generator generates a signal responsive to the movement. The signal operates a servo-drive mechanism that moves the light source a corresponding vertical distance along the rack and pinion assembly. This indicator visually defines the image plane located at the movable fulcrum of the tomography x-ray machine, and does not provide an indication of the longitudinal axis of the central x-ray beam as would be required when making transverse bores in a patient's bone in register with the bores of a osteosynthesis aid in the bone.
Laser light beams have also been used to calibrate tomography machines using phantoms as disclosed in U.S. Pat. No. 4,296,329, and for calibrating linear accelerators, or a cobalt-60 teletherapy machine as is disclosed in U.S. Pat. No. 4,123,660 and U.S. Pat. No. 4,223,227.